I just downloaded and activated the mailchimp plugin. When I go to the Mailchimp settings page, I enter my correct API key (verified) and the "Mailchimp Lists" dropdown displays, except there are NO LISTS populated.

1) yes my API is associated with 3 lists
2) when I use the same API with "Autochimp" those three lists are correctly displayed
3) because the dropdown box is empty I can never setup the signup form

So talked with the server admin, he's been working to get ftp working due to an issue between active and passive mode. He assures me that if there was an issue with outbound http traffic you wouldn't see any web pages. Perhaps I misunderstood your comment on the other thread.

Please let me know if there is a way forward or at least other places to check for this problem. I absolutely need to get mailchimp working ASAP.

@BoldBelvoir,
That isn't really a solution because they are both needed in order to fully maximize the mailchimp services. Without Autochimp there is no integration of users between WP and MC. Not to mention the loss of automailer when you publish a new blog post.

I Have been nuts trying to figure out why mine wasn't working on one blog but worked on another one (I have 2 .. one for my daughter with cancer and one for my website) I set up my daughters a while back back and it works perfect .. tried to set my own up and well .. not so much!

I ran right over the link that ecoevolver sent and grabbed the prior version .. went to my plugins and deleted the current version, uploaded the older one .. and poof back up and running again! THANK YOU

I used your API Key with the current version of the plugin in a WP 3.0.4 site and everything works fine. That means that something in your WP install is causing a conflict - probably a plugin or a theme. If we can figure out what and there's something to be done in our plugin to prevent that from happening, we'll look into that.

I'd imagine it's something else using our PHP wrapper and either not checking for it before loading it or expecting to use a different version of it.

Like the other folks here did, the first thing to try is disabling plugins one at a time until it starts working. If that's not it, it may require digging into the PHP error logs for you server to see if anything thing is being reported there.